1. Field of The Invention
The later-described embodiments relate to an electrode material exhibiting hopping conduction characteristics, and to an electrode layer, a battery, and an electrochromic device that use the electrode material.
2. Description of Related Art
For electrode materials, various materials such as metal oxides and carbons are used. International Publication No. WO 2013/146194 (Patent Document 1) discloses a battery electrode material using tungsten oxide powder.
As described in Patent Document 1, metal oxide powders such as tungsten oxide powder are subjected to a sublimation step using plasma treatment or the like to produce tungsten oxide powder (WO3). Further, in Patent Document 1, heat treatment is performed in an oxidizing atmosphere, in order to adjust the crystal structure of the obtained tungsten oxide powder. Such heat treatment allows tungsten oxide powder having a stabilized crystal structure to be obtained.
In this way, the crystal structure of the metal oxide powder used as an electrode material has been stabilized by performing the heat treatment in an oxidizing atmosphere. Further, storage characteristics (storability) are improved by stabilizing the crystal structure.
Meanwhile, in the case of using tungsten oxide powder subjected to heat treatment in an oxidizing atmosphere as an electrode material, as in Patent Document 1, no further improvement in storage characteristics was not seen.